A Physics Based Unified Circuit Model for Single Photon and Analog Detector

Mohammad Abu Raihan Miah,Yunrui Jiang,Yu-Hwa Lo

doi:10.1109/access.2021.3113301

Mohammad Abu Raihan Miah, Yunrui Jiang + Show 1 more

Open Access

https://doi.org/10.1109/access.2021.3113301

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Abstract

Photodetectors having an internal carrier multiplication mechanism such as avalanche detectors and recently discovered detectors with cycling excitation process (CEP) have attracted tremendous interests for their high sensitivity and flexibility of being operable in analog, sub-Geiger and Geiger mode. Detection of single or few photons in Geiger mode or sub-Geiger mode is particularly interesting as LiDAR systems are finding a wide range of applications in autonomous driving, augmented and virtual reality, robotics, imaging, sensing, and communications. In this paper, we present a universal detector equivalent circuit model, applicable to all modes of operation, for photodetectors with carrier multiplication gain. The bias-dependent gain, bandwidth, as well as gain buildup dynamics are rooted in device physics and translated into an equivalent circuit model that can be readily incorporated into integrated circuit design. The model simulates the characteristics of devices biased below and above breakdown voltage, making seamless transitions between analog, sub-Geiger, and Geiger mode with the same set of parameters directly obtained from the material properties. As a result, circuit designers can choose detectors using different gain medium (e.g., Si, InP, InAlAs) to simulate device effects on system performance. The circuit model is implemented in Orcad PSpice circuit simulator. Its wide applicability is demonstrated by simulating the device in linear, sub-Geiger and Geiger mode with external amplifiers and quenching circuits, as well as the gain-bandwidth product of detectors with a Si and InAlAs gain medium.

Highlights

Semiconductor photodetectors with inherent carrier multiplication gain such as avalanche detectors and more recently, detectors with cycling excitation process (CEP) produce high sensitivity in both conventional analog mode and in sub-Geiger mode or Geiger mode [1]–[3]
While avalanche photodetectors in analog mode can be modeled in photoreceiver circuits for optical communications with a relatively simple equivalent circuit model, the physical operation of avalanche photodetectors in sub-Geiger mode and Geiger mode is more complicated and is difficult to have an adequate equivalent circuit that relate the circuit parameters to the physical parameters of the devices and materials
We present a unified equivalent circuit model for photodetectors with built-in carrier multiplication gain such as avalanche photodetectors (APDs) and cycling excitation process (CEP) detectors

Summary

Introduction

Semiconductor photodetectors with inherent carrier multiplication gain such as avalanche detectors and more recently, detectors with cycling excitation process (CEP) produce high sensitivity in both conventional analog mode and in sub-Geiger mode or Geiger mode [1]–[3]. INDEX TERMS Active quenching, Avalanche, Circuit, Impact Ionization, LiDAR, Model, Passive quenching, PSpice, Single Photon Detector, SPAD It is most desirable to create a unified circuit model for detectors with avalanche or CEP gain that work for all modes of operations, i.e. analog mode, sub-Geiger mode, and Geiger mode.

Results

Conclusion